It is common is home construction and renovation to install large patio or sliding doors to permit ingress to and egress from a building or other structure while providing a very large visual opening to the outside. Due to the size of these sliding doors and there need to provide easy passage through the door, it may be desirable to have the lower sills of these sliding doors to be as low as possible. Such low sills provide less chance to trip or otherwise impede movement through the sliding door, when the door is open.
However, when the door is closed, it may be desirable to have a more significant sill height as the closed sliding door needs to also prevent water infiltration under the lower edge of the door. Since the lower edge of the sliding door positioned essentially at the floor level, the lower edge of the door will receive relatively less protection from any building overhangs and may be subjected to more rain, or wind-driven rain than a more traditional window. When excessive water enters the lower sill of the sliding from the outside, it is possible for this water to flow over the top of the lower sill and enter the building to which the sliding is attached or penetrate within the wall to which the door may be attached. Similar problems exist within regard to swinging doors as well.
While more traditional windows do not have the step over problem described above with respect to sliding doors, it is not uncommon for water to be trapped with such a window as well. Conventional approaches have incorporated passive weeping arrangements to allow trapped water to be removed from the window by gravity, but these approaches are not always effective and may become less effective over time with accumulated debris or growth. Further, an exceptionally tall sill height is not desirable in traditional windows as such a raised sill can obscure a portion of the view through the window or fenestration opening.
Improvements to conventional sliding doors and windows are desirable to provide for a lower sill height while ensuring that water infiltration over the lower sill in minimized.